The Mount Sakurajima volcano is in a state of near-perpetual eruption, with more than 600 minor explosions this year, the BBC reported. But when it started spewing ash Tuesday at 7:15 p.m., residents knew it wasn’t a trivial flare-up. The eruption sent 18-inch rocks more than a mile through the air

Repeated eruptions from the Sakurajima volcano have produced large amounts of ash draping the city center Sept. 15, the Kagoshima Local Meteorological Agency said.

Eruptions from the volcano overlooking the city of Kagoshima began on Wednesday morning, dumping 217 grams of ash per square meter 7 ounces per 10 square feet, the third-highest level of ash to fall since records began in 1994.

Volcanic ash covered much of Kagoshima’s Tenmmonkan entertainment and business district on Thursday morning, visibly forming clouds as cars drove through it and many pedestrians covering their faces with towels or surgical masks to avoid breathing it in.

Sakurajima is an active volcano that regularly erupts, though its most deadly eruption in post-feudal Japan was almost a century ago, when 35 were killed in 1914.

The explosion shook buildings for miles and happened in Sakurajima Minamidakein Kagoshima at 4:45p.m. on October 3rd. The smoke went 3000m above the mountain. The explosion of the caldera near the top of the mountain, which is one of two craters of Minamidake, last erupted on February 22nd. The shock-wave was huge and it was possible to hear the sound of the explosion in Kagoshima city which is on the other side of the ocean.